Means for producing alpha straight-line motion of lenses



y 1, 1930- w. E. JOHN 1,768,772

mus FOR rnonucme A STRAIGHT LINE nonou or LENSES Fileici Nov. 5

Patented July 1, 1930 UNITED STATES PATENT OFFICE MEANS FOR PRODUCING A STRAIGHT-LINE MOTION OF LENSES Application filed November 5, 1927, Serial No. 281,199, and in Great Britain February 15, 1927.

The presentinvention refers to systems in which a series of bodies is propelled, by rotary mechanism, through a closed path Comprising a rectilinear section occupied 5 by several of the bodies simultaneously;

throu h which section the bodies are reuire to be moved at a speed having a xed velocity ratio to the rotary driving mechanism.

Such systems have practical application in kinematograph apparatus in which the film is constantly moved and in which the bodies are carriers for lenses optically compensating for the film movement;

which the bodies are unconnected and push one another through a fixed guide defining the rectilinear sectlon.

The invention provides a construction in which the propellin force can be applied to the bodies central y of their length, thus avoidin the longitudinal tilting to which the bodies are liable in case the propelling force is applied by gear teeth engaging their ends, as is necessary in some constructions. This'result is attained according to the invention by propelling1 the bodies by means of an internall toot ed wheel having, be tween the teet spaced pockets in which the bodies'are received; part of the pitch circle of the wheel being a part of the closed path of the bodies and the bodies being guided from said wheel into the rectilinear path. This arrangement also enables the pushi action to be confined to those of the b0 ies which are in the rectilinear section and those. immediately adjacent the ends of such section.

An example of 'the invention is illustrated in t e accompanying drawings in which- Fig. I is a face view of a kinematograph mechanism with part of the front cover (13 Fig. II) broken away and some of the bodies in section.

Fig. II is a section on IIII Fig. I.

Fig. III is an enlarged perspective view of the upper part of Fig. I.

2 is a thick disc fitted with a cover plate 3.

The disc is peripherally cut away to pro- The present invention is of that type in.

vide an annular channel 4 and is slotted on a chord to provide a rectilinear channel 5 communicating with the annular channel.

The disc and cover plate form a journal for the rotatable wheel 6. Said wheel is provided with appropriate means for rotating it, indicated by the pinion 7 meshing with external teeth 8 on the wheel. These parts constitute the rotary driving mech-. anism with which the rectilinearly guided bodies have to maintain a constant velocity ratio.

The wheel 6 has an internal flange 9 which enters the channel 4, and so retains the wheel axially in position. Said flange is provided with internal teeth 10 forming between them pockets 11 for the reception of the lens casing 12. Said casings are externally cylindrical, the pockets 11 being correspondingly of approximately semi-cylindrical form. Towards their ends the cylinders are provided. with flanges 13, 14 and shields 15 for the purposes mentioned below.

The closed path of the centres of the cylinders 12 comprises the portion A-B of the pitch circle of the Wheel 6, the transition curve B-O, the rectilinear path C-D and the transition curve DA.

In the,section A-B of their path the cylinders are carried in the pockets 1-1 and are retained therein by the cylindrical shoulder 16 of the disc 2.

In the straight section C-D they are constrained by the plane guide surfaces of the slot 5. Within this section the lenses are exposed through the openings 17. In the transition curve B-C the cylinders pass out of the wheel 6 and are constrained, by the guide surfaces 18, to the straight guide 5 Similarlyin the curve DA they are guided by guide surfaces 19 back into the wheel 6. So much of the guide surfaces 18 and 19 as is cut out of the disc 2 by the formation of the channel 4, is provided by inserted pieces 20.

From B to A the cylinders are in contact with and push one another; their motion being derived from that tooth 10 of the wheel 6 which is driving the cylinder leaving the pitch circle. Themotion in this section is preferably upwards so that the cylinders are held in contact with one another by gravity.

In the pitch circle arc A-B the cylinders are spaced apart, giving a substantial driving tooth 10 between each pocket 11 which is not possible if it is attempted to apply a driving wheel centrally to the cylinders packed in the straight path. The diameter of the pitch circle, the spacing of the cylinders therein, and the length and shape of the path section BA are so proportioned to the diameter of the cylinders as on the one hand to fill the path section BA suiiiciently to ensure that the uppermost cylinder in it will be properly received into its pocket 11, and on the other hand to ensure that there shall be no break in the driving contact of the last tooth 10 with the cylinder passing out of the pitch circle.

In the example shown, the path C-D is on a diameter of the pitch circle. This gives a satisfactory form to the driving tooth face 21 and has manufacturing advantages.

lVhilst the transition path B-C has necessarily to be arranged to maintain uninterrupted contacts from tooth 10 through to the last of the exposed cylinders, the transition path DA is so arranged as to relieve the close packing of the cylinders and so avoid any danger of the cylinder train becoming jammed. It is accordingly made rather longer and of greater radlus than the path B-C; this latter feature also enabling the teeth 10 to be kept sufficiently long to maintain contact with the cylinder which is being driven into section BC.

Measurements suitable for meeting the above conditions are:

Diameter of cylindrical lens casings, 1 unit;

Number of lens casings, 1st;

Number of pockets (ll), 18;

Diameter of pitch circle AB, 6.64: units;

Path section C--D lies on a diameter of A-B;

Radius of arc BC, 1 unit;

Radius of arc DA, 1.24: units.

The driving tooth faces 21 are empirically shaped to maintain contact with the cylinder leaving the pitch circle while the wheel 6 rotates at constant speed and while the cylinders of the rectilinear section CD move at constant speed; thus ensuring a constant velocity ratio between the wheel and the cylinders in CD.

lVhile the cylinders are being directly transported by the wheel 6 they are stationary within the pockets 11 and therefore not subjected to wear. \Vhen they are within the straight path they slide in the guide 5; and tc give them adequate sliding contact area to resist wear, they are provided with the flanges 13, 14: the fiat end faces 22 of which make contact with the guide 5. Said end faces may be tangent to the cylinder so that they and the periphery of the cylinder contact simultaneously with the guide.

The side edges 23 of the flanges 13 may be tangent to the cylinder and at right angles to the end faces to provide bearing surfaces by means of which the cylinders press upon one another when passing through the guide 5. The flanges 11 however have sloping sides 21 to permit the cylinders to be positioned angularly to one another, in the curved portions of their path.

The inner shoulders 25 of the wheel 6 and the shoulder 16 of the disc 2 engage the end faces of the flanges 13 and 1d sufiiciently closely to ensure that said flanges will be properly positioned when they are presented to the guide 5. Clearances 26 are cut to clear the corners of the flanges 13 when the cylinders are passing through the transition curves B-C and D-A.

The shields 15 are provided for the purpose of blinding the triangular gaps 27 (Fig. III) left between the flanges 14 of the lenses which are being exposed. They are provided at the opposite ends of successive cylinders to allow them to overlap in the axial direction of the lenses. The end of the lens casing which does not carry a shield is cut away at 28 to give clearance to the corners of the adjacent shields as they tilt in the curves B-C and DA.

I claim 1. The combination of a number of simi lar loose bodies and means defining a closed path through which said bodies are pushed,

said means including guide surfaces defining a rectilinear section of the path, and an internally toothed wheel part of the pitch circle of which defines another section of the path, the rectilinear path being on a chord of the pitch circle.

2. The combination of a number of similar loose bodies and means defining a closed path through which said bodies are pushed, said means including guide surfaces defining a rectilinear section of the path, and an internally toothed wheel part of the pitch circle of which defines another section of the path, the rectilinear path being on a diameter of the pitch circle.

3. The combination of a number of similar loose bodies and means defining a closed path through which said bodies are pushed, said means including guide surfaces defining a rectilinear section of the path, an internally toothed wheel part of the pitch ircle of which defines another section of th path, and guides defining transition curves between the pitch circle and the rectilinear section, the transition curve at one end of the rectilinear section being of greater radius than that at the opposite end of said 5 ection thereby to maintain constant con- ISI tact through a series of the bodies beginningwith the one about to leave the wheel and including those in the rectilinear section.

4. The combination of a number of similar loose bodies and means defining a closed path through which said bodies are pushed, said means including guide surfaces defining a rectilinear section of the ath, an internally toothed wheel part 0? the pitch circle of which defines another section of the path, and guides defining transition curves between the pitch circle and the rectilinear sectionthe transition curve giving exit from the rectilinear section-being longer than the other transition curve to avoid close packing of the bodies between the rectilinear section and the wheel.

5. The combination of a number of loose cylindrical bodies, an internally toothed driving wheel adapted to receive such bodies between its teeth, a rectilinear guide for the bodies, curved guides guidin the bodies from the wheel into one end 0 the rectilincar guide and from the other end of the rectilinear guide back into the wheel, and flanges on the bodies havin fiat end faces which contact with the recti inear guide.

6. The combination of a number of loose cylindrical bodies, an internally toothed driving wheel adapted to receive such bodies between its teeth, a rectilinear guide for the the bodies bodies, curved guides guidin from the wheel into one end 0 the rectilincar guide and from the other end of the rectilinear guide back into the wheel and flanges on the bodies having fiat edges which contact with one another when the bodies are in the rectlinear guide.

7. The combination of a number of loose cylindrical bodies, an internally toothed driving wheel adapted to receive such bodies between its teeth, a rectilinear guide for the bodies, curved guides guiding the bodies from the wheel into one end of the rectilinear guide and from the other end of the rectilinear guide back into the wheel, contact-making flanges on the bodies sloped to permit the bodies to pass around curves, and shields to blind the gaps left between the sloped flanges.

8. The combination of a number of similar loose bodies and means defining a closed path through which said bodies are pushed, said means including guide surfaces defining a rectilinear section of the path, and

an internally toothed wheel part of the pitch circle of which defines another section of the path, the rectilinear path being on a chord of the pitch circle and the teeth of the wheel having driving faces adapted to maintain contact with said bodies during their passage to the rectilinear section thereby to impart to the bodies in said section a constant velocity relatively to the velocity of the toothed wheel.

9. The combination of means defining a closed path through which a number of loose bodies are pushed, said means including guide surfaces defining a rectilinear section of the path, an internally toothed wheel part of the pitch circle of which defines another section of thepath, and guides defining transition curves between the pitch circle and the rectilinear section, and a number of similar loose bodies, a group of which completely fills that portion of the path which consists of the rectilinear section and the transition curve iving entry to the rectilinear section, sai' group including the body about to leave the wheel and each body in said group being in physical contact with the next, the remainder of the bodies occupying the remainder of the path but incompletely filling the same.

Signed atJOhanneSburg, Transvaal Province, Union of South Africa, this ith day of October, 1927.

' WESLEY ERNEST JOHN. 

